Gray-New Gloucester High School has moved to remote learning until after the Thanksgiving break following two unrelated positive COVID-19 cases that have contributed to a staffing shortage.

The two cases were a student and a teacher, and all close contacts have been notified. The closure was announced Monday and the high school will reopen Nov. 30, School Administrative District 15 Superintendent Craig King said Tuesday.

“Although we had two confirmed cases of COVID-19, this was not the driving factor in closing the high school,” King said in an email. “Confirmed cases can be quarantined at home allowing the school to remain open and functioning safely.

“The primary reason we closed the high school is due to a critical shortage of substitute teachers and substitute support staff. The confirmed COVID-19 cases exacerbated the existing substitute problem.”

There are currently no cases or suspected cases at any of the district’s four other schools.

Like other districts around Maine, SAD 15 opened the school year in a hybrid model with students attending in-person two days per week. The district also has a fully remote option, which was selected by 18 percent of students.

Several schools around Maine have had to close for days or weeks in response to cases and outbreaks and hundreds of students and staff have had to quarantine after coming in close contact with infected individuals.

As of Thursday, there were 196 confirmed or probable cases reported in Maine schools in the last 30 days, including seven outbreaks of three or more cases. The Maine Department of Education tracks all cases and updates its list twice a week.

Dr. Nirav Shah, director of the Maine Center for Disease Control and Prevention, said Monday that most transmission is happening outside school buildings in communities.

“Keeping kids in schools with in-person learning continues to be one of our priorities,” Shah said. “We have seen very little transmission of COVID-19 within the four walls of the school.”